# Vitriol

**Vitriolum*; copperas*

**Known today as.** Green vitriol (iron sulfate), blue vitriol (copper sulfate), and white vitriol (zinc sulfate); “oil of vitriol” is sulfuric acid.

Kind: Mineral  
Poisoning: Mercury, arsenic, lead, and antimony (https://thethinkingpress.org/materia-medica/poisons/heavy-metal)  
Toxic: yes

> **Caution.** Copper and zinc vitriol and oil of vitriol are poisonous or corrosive.

## What was it used for?

Astringent and caustic, for wounds, ulcers, and the eyes; the base of ink with oak galls.

## What does modern science say?

Iron sulfate still treats iron deficiency; the others are poisonous by mouth.

## Pharmacognosy and toxicology

- **iron(II) sulfate**: green vitriol
- **copper(II) sulfate**: blue vitriol
- **zinc sulfate**: white vitriol

**Mechanism.** Copper sulfate corrodes the gut and destroys red cells; it was given as an emetic until the 1970s, and remains a common means of suicide in India. Iron sulfate is the standard treatment of iron deficiency, and an overdose of iron tablets kills children.

**Dose.** About 10–20 g of copper sulfate; iron above 60 mg per kilogram in a child.

**Standing.** Ferrous sulfate is on the WHO list of essential medicines; copper sulfate has no medical use.

## What did the older authorities say?

**The alchemists.** Read its name as an acrostic: *Visita interiora terrae rectificando invenies occultum lapidem*, “visit the interior of the earth, and by rectifying you will find the hidden stone.” See [Alchemy](https://thethinkingpress.org/inspirations/alchemy).

## Sources

- Basil Valentine (attributed), *Currus triumphalis antimonii* (1604).
- Franchitto, N., et al. (2008). “Acute copper sulphate poisoning: a case report and literature review.” *Resuscitation* 78.

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*Vitriol.* In *Materia Medica*, edited by B. C. P. Statema. Version 1, revised 2026-09-25. The Thinking Press. https://thethinkingpress.org/materia-medica/vitriol

Historical description, not medical advice.